Textbook Question
By using the data in Appendix E, determine whether each of the following substances is likely to serve as an oxidant or a reductant: (a) Cl2(g), (b) MnO4- (aq, acidic solution), (c) Ba(s)
Ch.20 - Electrochemistry
Brown15th EditionChemistry: The Central ScienceISBN: 9780137542970
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Table of contents
- Ch.1 - Introduction: Matter, Energy, and Measurement146
- Ch.2 - Atoms, Molecules, and Ions200
- Ch.3 - Chemical Reactions and Reaction Stoichiometry176
- Ch.4 - Reactions in Aqueous Solution155
- Ch.5 - Thermochemistry126
- Ch.6 - Electronic Structure of Atoms131
- Ch.7 - Periodic Properties of the Elements126
- Ch.8 - Basic Concepts of Chemical Bonding123
- Ch.9 - Molecular Geometry and Bonding Theories143
- Ch.10 - Gases147
- Ch.11 - Liquids and Intermolecular Forces91
- Ch.12 - Solids and Modern Materials122
- Ch.13 - Properties of Solutions126
- Ch.14 - Chemical Kinetics174
- Ch.15 - Chemical Equilibrium101
- Ch.16 - Acid-Base Equilibria139
- Ch.17 - Additional Aspects of Aqueous Equilibria146
- Ch.18 - Chemistry of the Environment72
- Ch.19 - Chemical Thermodynamics129
- Ch.20 - Electrochemistry142
- Ch.21 - Nuclear Chemistry101
- Ch.22 - Chemistry of the Nonmetals68
- Ch.23 - Transition Metals and Coordination Chemistry66
- Ch.24 - The Chemistry of Life: Organic and Biological Chemistry10
Brown15th EditionChemistry: The Central ScienceISBN: 9780137542970Not the one you use?Change textbook
Chapter 20, Problem 47a,b,c
From each of the following pairs of substances, use data in Appendix E to choose the one that is the stronger reducing agent: (a) Fe(s) or Mg(s) (b) Ca(s) or Al(s) (c) H2(g, acidic solution) or H2S(g)
Verified step by step guidance1
Identify the standard reduction potentials for both Fe(s) and Mg(s) from Appendix E. The standard reduction potential is a measure of the tendency of a chemical species to be reduced.
Compare the standard reduction potentials of Fe(s) and Mg(s). The substance with the more negative standard reduction potential is the stronger reducing agent.
Recall that a stronger reducing agent has a greater tendency to lose electrons, thus it is more easily oxidized.
Write the half-reactions for the reduction of Fe(s) and Mg(s) to understand how they gain electrons during the reduction process.
Conclude which substance is the stronger reducing agent based on the comparison of their standard reduction potentials and their tendency to lose electrons.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Reducing Agents
A reducing agent is a substance that donates electrons in a chemical reaction, thereby reducing another substance. The strength of a reducing agent is determined by its ability to lose electrons easily. Stronger reducing agents have a greater tendency to undergo oxidation, which is the loss of electrons.
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01:01
Oxidizing and Reducing Agents
Standard Reduction Potentials
Standard reduction potentials (E°) are measured values that indicate the tendency of a species to gain electrons and be reduced. These values are typically listed in tables, where a more positive E° value corresponds to a stronger oxidizing agent and a more negative value indicates a stronger reducing agent. Comparing the E° values of the substances in question helps determine which is the stronger reducing agent.
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01:10Standard Reduction Potentials
Electrochemical Series
The electrochemical series is a list of standard reduction potentials for various half-reactions, arranged from the strongest oxidizing agents to the strongest reducing agents. By examining this series, one can predict the direction of redox reactions and identify which substances will act as reducing or oxidizing agents. This series is essential for comparing the reducing strengths of different metals.
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Related Practice
Textbook Question
The standard reduction potentials of the following halfreactions are given in Appendix E:
Ag+(aq) + e- → Ag(s)
Cu2+(aq) + 2 e- → Cu(s)
Ni2+(aq) + 2 e- → Ni(s)
Cr3+(aq) + 3 e- → Cr(s)
(a) Determine which combination of these half-cell reactions leads to the cell reaction with the largest positive cell potential and calculate the value.
(b) Determine which combination of these half-cell reactions leads to the cell reaction with the smallest positive cell potential and calculate the value.
Textbook Question
By using the data in Appendix E, determine whether each of the following substances is likely to serve as an oxidant or a reductant: (d) Zn(s)
Textbook Question
A voltaic cell consists of a strip of cadmium metal in a solution of Cd(NO3)2 in one beaker, and in the other beaker a platinum electrode is immersed in a NaCl solution, with Cl2 gas bubbled around the electrode. A salt bridge connects the two beakers. (a) Which electrode serves as the anode, and which as the cathode? (b) Does the Cd electrode gain or lose mass as the cell reaction proceeds? (c) Write the equation for the overall cell reaction.